Related

After he was listed on this year's TIME 100 poll to determine the world's most influential people, Chinese author Han Han wrote a blog post announcing, "Other Chinese nominees include sensitive word, sensitive word and sensitive word." It was something of an inside joke, but one that Han's huge fan base would immediately get. "Sensitive word" was a jab at China's Web censors' habit of sometimes blocking even commonplace names from display in blog posts and Web searches. Within days, his post had generated more than 20,000 comments, most in support of the writer, a few in opposition and many grumbling about the state of online freedom in China.

Critics of China's censorship regime have often predicted that information will inevitably circumvent efforts to restrict it. But so far China has managed, through a variety of means, to restrict the discussion of topics the government finds objectionable, such as independence drives in the regions of Tibet and Xinjiang and the banned religious movement Falun Gong.

For the tens of thousands of censors employed by the government, blocking access to restricted information both at home and abroad is an ongoing struggle. Their work is mirrored by employees of large Web portals who ensure content conforms with official directives. With what is called the "Great Firewall of China," authorities block access to overseas Web pages deemed objectionable and shutter domestic sites that repeatedly stray into restricted territory. Search engines are prevented from linking to sensitive content. Mainland media, which face a host of regulations that limit how they can report the news, are often forced to take down controversial stories that have been posted online. (See pictures of Chinese mourning the loss of Google.)

Despite those restrictions, the Internet in China roils with debate over current events. China now has an estimated 384 million Internet users, more than the total population of the U.S. That size, combined with the growing popularity of interactive applications that allow users to generate their own content, has placed great strain on censors' ability to restrict the flow of sensitive information. Often news happens and discussion spreads widely before censors have a chance to decide how to manage the subject. "In this war, the censor is obviously not winning," says Xiao Qiang, the director of the China Internet Project at the University of California, Berkeley. "In the interactive space, users are winning by numbers."

Perhaps the greatest threat China's censorship regime now faces is that it can't seem to stop debate over censorship itself. Since Google declared in January that it planned to stop censoring its Web search results in China, the state of online censorship has come under increasing scrutiny. The Chinese government has sought to portray its conflict with the Internet giant as a commercial dispute and a simple matter of law. But to a significant number of Chinese Web users, the extensive Web restrictions increasingly chafe. So they make use of widely available proxies and virtual private networks to fanqiang, or "climb the wall," for access to everything from politics to porn. Censors can further restrict access to overseas sites by slowing or blocking the networks used to bypass the Great Firewall, says Xiao, but they are reluctant to do so for fear of interfering with commercial applications, like secure communications between corporate offices. (See who will profit when Google exits China.)

In 2006 Jason Ng, a blogger from Guangdong province in south China, began writing about how to circumvent censorship in China after he read about the government's block on Wikipedia, the user-generated online encyclopedia. He started by posting technical tips and essays on various bulletin boards and his own blog on sina.com, a major Chinese Web portal. "During that time, many of my posts were either quietly deleted or unable to get published on my blog for no reason," he says.

Pent-up frustration led Ng to create his own website, kenengba.com, in April 2007. The site  its name means maybe  gained attention last year among Chinese Web users who opposed a government plan to require the installation of software on new computers that would block some websites. The Ministry of Industry and Information Technology's proposal was promoted as a way to restrict pornography, but most of the targeted websites were political. In August 2009 the agency dropped the requirement to install the software, known as the Green Dam Youth Escort, after widespread protest from Web users and foreign computer makers.

Since then, Ng says, he has received phone calls and e-mails from government officials ordering him to remove articles that teach users how to circumvent Web restrictions, or else his website would be shut down by authorities. This has left him with little choice, he says, but to switch to an overseas server. In late March, when Google began redirecting Chinese search traffic to an uncensored site based in Hong Kong, authorities blocked Ng's site. His daily traffic dropped from more than 20,000 hits to 6,000 overnight, but many mainland users still climb the Great Firewall to view his site.

The phenomenon is happening in much larger numbers on Twitter, where thousands of Chinese users post information about current events in China despite the site's being blocked by authorities. When the activist lawyer Gao Zhisheng reappeared in March after disappearing in police custody more than a year ago, the news was first revealed on Twitter and then spread to the mainstream press. Ai Weiwei, a Chinese artist who has organized an investigation into the deaths of children whose schools collapsed in the 2008 Sichuan earthquake, has been active on Twitter over the past year; he now has 33,000 followers. Recently he began posting birthday memorials for students who died in the quake. In a recent interview with CNN, Ai, who helped design the "Bird's Nest" Olympic stadium in Beijing, predicted that social media would one day overcome China's censorship regime.

Because mainland users have to climb the Great Firewall to access Twitter, they generally share an interest in issues of free speech, says Xiao. They discuss news in the unfiltered medium of Twitter and then repost information on mainland blogs and Twitter-like microblogging services. "It is not a fluke," he says. "It's a pattern. The Chinese censors look at this space with great focus and are trying to figure out what to do with it."